It is well known that a significant number of accidents result from drivers of vehicles becoming distracted, drowsy or falling asleep, which results in many deaths and injuries. It is also known that safety may be improved by alerting a driver of pending danger.
A number of different physical criteria may be used to establish when a person is drowsy, including eye movement, a change in the duration and/or interval of eye blinking, head position (e.g. tilting), a physiological change (e.g., altered heartbeat or breathing) and the physical result of the driver falling asleep (e.g., a reduced grip of the steering wheel). Further, unintended movement of the vehicle from one lane to another may be an indication of a drowsy or distracted driver (unless, of course, a turn signal has been activated).
Some of these physical criteria, such as eye movement, blinking and lane departure, can be detected using cameras.